Fitted sieve frames



J. D. EMNGHAM 3,193,098

FITTED SIEVE FRAMES 2 sheets-snee@ i July 6, 1965 Filed May 18, 1962 July 6, 1965 '.1. D. BINGHAM FITTED SIEVE FRAMES 2 Sheets-Sheet 2 Filed May 18. 1962 United States Patent O 3,193,098 FITTED SIEVE FRAMES `lohn D. Bingham, Bramhall, England, assigner to Henry Simon Limited, Stockport, Cheshire, England, a British company Filed May 18, 1962, Ser. No. 195,877 tClaims priority, application Great Britain, .lune 12, 1961, 21,093/ 61 1 Claim. (Cl. 209-404) The invention relates to fitted sieve frames wherein a woven fabric or similar screen is fixed to a shallow square or rectangular framework arranged for mounting in retaining guides in a sieving machine, and particularly refers to metal sieve frames which are mounted in a series group in common retaining guides so that all the screen surfaces in the series lie on a common plane.

With such an arrangement, it is desirable that the frames in the series shall be interlocked so that they can all be withdrawn from one end of the retaining guides, and it is also desirable that the joints between the individual frames shall be guarded so that material in transit along the series of sieves cannot leak through the joints into the throughs fraction of material. Further, it is an important requirement of sieves employing woven fabric or similar screens that where the process of sieving necessitates the passing of particulate material along the sieve surface, the fabric or like comprising such surface shall be maintained in a taut sag-free condition.

The object of the present invention is to provide a rigid metal-framed fitted sieve having the above desirable features and incorporating novel means for achieving and maintaining a required condition of tautness in the screen fabric.

According to the invention, a sieve frame comprises end and side channel members with their parallel flanges extending outwards, at least one end and one side member having a yoke element, to which the sieve cover is attached, arranged in the channel to be adjustable transversely therein, and the end members having their lower parallel flanges arranged to interlock with those of the end members of adjacent sieve frames.

In accordance with further features of this invention, a fitted sieve frame of the type referred to and wherein the frame comprises a rigid comparatively shallow foursided open metal framework having side members which are substantially channel-shaped in cross-section and arranged with their parallel flanges facing horizontally outwards, is characterized in that on at least two adjacent sides of the framework the clamping means whereby the woven fabric or similar screen is fixed in association with a related side of the sieve framework forms part of a vertically slidable yoke element housed within and extending along the full length of the associated framework member and arranged so that without any alteration of the screen clamping condition the said yoke element can be adjustably moved to alter the tension applied to the fabric of the screen, and also characterized in that on one of the sides of the frame the lower of the parallel fianges is extended outwardly and upwardly over its whole length whereas the side directly opposite has its lower parallel anges extending outwardly and downwardly over its whole length, the respective upward and downward extensions being arranged so that when such frames are engaged in series hook couplings are formed which ICC extend over the full length of the abutment joints `be tween the sieves to effectively prevent material that passes through the joint from mixing with material which has passed through a screen fabric. The hook couplings also provide means whereby a series of sieve frames can be manipulated from one end of the retaining guides in which they are supported.

Referring to the accompanying drawing:

FIGURE 1 is a plan view of a sieve frame according to the invention.

FIGURE 2 is a section on the line II-II of FIGURE 1 the view looking in the direction of the arrows.

FIGURE 3 is a section on the line III-III of FIGURE 1 the view looking in the direction of the arrows.

In the preferred embodiment of the invention shown in the drawing, the sieve frame has two longitudinal frame members 1, 2 which when the frame is in use rest in the retaining guides of an associated sievng machine and are parallel to the direction of motion of the material being sieved. The members 1, 2 have identical channel-shaped cross-sections with parallel flanges 3, 4 and 5, 6 which extend outwardly by the same amounts. These longitudinal members 1, 2 are welded at their ends to two transverse frame members 7, 8 which are also substantially channel-shaped in cross-section but in these members the lower outwardly extending parallel anges 9, 10 are extended beyond the upper flanges 11, 12 and in the case of the member 7, the flanges 9 is upwardly turned at its edge to form an upwards facing hook element 9a which extends continuously along the member 7, whereas in the other transverse member 8 the extended lower parallel flange 10 is downwardly turned at its edge to form a downwards facing hook element 10a extending continuously along the member 8 and of a shape which is complementary to that of its opposite flange 9 so that when such frames are arranged in series, the hook elements 9a and 10a may be interlocked to hold the frames together and to provide a seal against leakage of material which may fall through the joint between the surfaces of the sieves.

The upper parallel flange 12 of the transverse frame member 8 which has the downwardly facing hook element, is sufficiently thick to include along its outer edge a substantially half-round groove 13 which runs along the full length of the member 8. This groove forms a locking trap for one edge of the screen fabric 14 which is clamped in position by a matching half-round retaining bar 15 that is fixed in the groove 13 by a plurality of screws.

The screen fabric 14 is secured along its other three sides in a similar manner but in these instances the 1ock ing trap grooves are not in the webs of the frame but grooves 16a are formed in the outwardly directed face of vertically slidable yoke elements 16 which are housed within the span of the horizontal parallel flanges 4, 6, 11 of the associated frame members 1, 2, 7 and extend along the whole lengths thereof, the said yoke elements 16 being adjustably secured in position by a plurality of thrust screws 17 which are freely journalled in holes in the associated lower parallel flanges 3, 5, 9 and are in screw-thread engagement with the slidable yoke element 16, with the ends of the screws 17 being arranged to thrust against the underside of the upper parallel flanges 4, 6, 11.

In a fitted sieve frame as described, adjustment of the tension in the screen fabric 14 is leifected by causing the yoke elements 16 on two adjacent sides of the frame to be moved vertically within the related frame members by manually rotating the thrust screws'l'l associated therewith.l j f Y Y What is claimedis: Y l An all-metal sieve frame vcomprising a pair of parallel side'mernbers and a pair ofV parallel end members inter-` connected thereto to provide: a rigid comparatively shallow rectangular.v open framework, saidparallelfside and end members being'of substantially channel shape in cross section and having parallel upper and lower flanges projecting outwards,'the Yupperllange YOi one of theend` members having a groove therein extending the full length thereof, a vertically slidablefryoke element located between the upper and lower anges of the other end member and between the upper andy lower anges of veach of the Vside Y members, each yoke element extending the entire Vlength of its associated member and having an outwardly directed face providedwith agroove therein, retaining Ybars of substantially the same length as said side and end members positioned in said grooves for clamping the edges of a screen ,fabric disposed over the upper flanges of the side j and end members, kmeans for moving eachyoke element vertically `so that without any alteration ofthe screen fabric clamping condition, each yoke element. can be moved for changing the tension applied to the screen fabric, the lower flange ofoney of said end members being extended outwardly beyond the corresponding upper ilange and terminating in an upwardly turned hook clement,'and the lower flange of the other end member bev ing spaced above the bottom of said end member and'extended outwardly beyond the corresponding upper flange and terminating in a downwardly turneclv hook element complementary to the rst named hook element whereby a pluralityof sieve frames can be positioned in end-toend series with adjacent hook elements in engagement thereby preventing any material which may pass through the frameV junctions from mixing with material which has passed through the` screen fabric; v i

References Cited by the Examinerl vUruTED STATES PATENTS HARRY B. THORNTON, Primary Examiner. HERBERT L. MARTIN, Examiner.' Y 

